This invention relates to an electronic analog display device including an electronic display unit such as a liquid crystal display unit, in which numerical data to be displayed on a display device are displayed as analog data such as patterns by a driving method according to a two-dimensional matrix address system.
Heretofore, an analog display device having an electronic display unit such as a liquid crystal display has displayed analog data according to a lighting method in which some of the display elements forming the display unit are turned on, or a number display elements in alignment are turned on. It has been attempted to selectively operate the display elements according to the former lighting method so that the configuration of the display elements thus operated appears similar to a pointer of a mechanical analog display device; that is, like the moving hand of a clock.
U.S. Pat. No. 4,044,345 to Ueda, commonly assigned, discloses a method of addressing display cells arranged in an X-Y matrix which is similar to the addressing method of the invention. In this patent, the scanning voltages applied to the scanning electrodes assume a high level during only one particular time slot of a given cycle. The signal voltages are varied in the slots having the high level so as to effectively select elements of the display which will and will not receive a voltage in excess of the threshold.
Also in an article by Shanks et al., Displays, April, 1979, p. 33.sup.+ entitled "Non-Multiplexed Addressing Methods for Liquid Crystal Oscilloscope Display ", there is discussed a liquid crystal display for use as a replacement of a conventional oscilloscope CRT, which again uses an addressing method and a display apparatus somewhat similar to the invention.
However, the conventional analog display devices are disadvantageous in that when it is required to display a mechanical configuration, such as for instance the configuration of the hand or pointer of a clock, with the display elements, it is impossible to smoothly display the movement of the pointer because the display elements for displaying the pointer must be arranged in one and the same plane without being overlapped. In order to overcome this drawback as much as possible, an analog display device has been proposed in the art, in which, among a series of display elements, a predetermined number of serial ones are lighted in a manner such that only two display elements at the front and rear ends are changed at a time, to display a smooth movement. However, this device is also disadvantageous in that the configuration of the displayed pattern is too rough to be recognized as a pointer.